Season one-billion of American Idol hasn't even started yet, and already we're thinking about the end. Simon Cowell, beloved grumpy crumpet judge, will leave at the end of the season to judge the similarly-themed British import, The X Factor.

The show has the same basic set-up — young unknown singers compete for audience votes and get lambasted by a panel of three — with Cowell himself serving as a judge during his Idol-free downtime. The X Factor will premiere fall 2011, then move to the summer for subsequent seasons, with Idol still dominating the winter/spring. Cowell's departure was long-rumored, as fellow original judge Paula Abdul left the show earlier this year and ratings had begun to gradually (very gradually) slow down. Cowell is also said to have had major disagreements with Idol producer Simon Fuller, so presumably X Factor offered him the opportunity to be a bit more sovereign. Whatever Cowell's reasons, the real questions are 1) whether Fox really has room for two singing competition shows (will the presence of both will split the vote and dilute the programs' influence and ability to actually create pop stars?), and 2) what the heck is Randy Jackson going to do all by himself next year? Sad, dawg. [NYT]

Update!TMZ is saying that gurgling hair-mound Paula Abdul has been in talks with Cowell to join him on X Factor. Once again, poor Randy.